Conoclinium coelestinum

Also known as Mistflower, Wild Ageratum, Blue Boneset

Blue mistflower brings intense clouds of lavender-blue color to moist meadows, stream banks, and ditch margins throughout late summer and autumn. Lacking ray petals entirely, its fuzzy floral heads consist solely of tubular disc florets with long, thread-like styles that attract a wide array of butterflies and native bees. Spread vigorously by creeping rhizomes, it forms dense colonies that stabilize wet soils and provide critical late-season nectar.